Soluble oil



Patented Sept. 7, 1943 UNITED STATES PATENT OFFICE r. by p ny. ware mesne assignments, to The Texas Com- New York, N. Y., a corporation of Dela- No Drawing. Application August 9, 1940, Serial No. 351,990

17 Claims.

This invention relates to soluble oils comprising petroleum oils which disperse readily when added to water. Oils of this type are used, for example, in the preparation of aqueous emulsions for use as a, cooling and lubricating fluid in metal working operations, such as the grinding, cutting, and turning of metals, and as a slushing oil for the protection of metal surfaces against oxidation.

In metal working, it is essential that the emulsion provide sufflcient lubrication and cooling, and the emulsion should not corrode or rust metals. In such operations as grinding operations, the emulsion should permit rapid settling of the removed metal and abrasive particles so that they will not be carried over to subsequent work, should keep the grinding surfaces clean, and should wet the work uniformly. The emulsion should not be materially aifected by hard water. Some of the prior emulsions were unstable in hard water, and an attempt to remedy this by softening the water resulted in objectionable foaming.

It is an object of this invention to produce a soluble oil which is superior to soluble oils used in the past, since none of the prior soluble oils fully met the various requirements.

It has now been discovered that the requirements enumerated and other requirements are particularly well met by a soluble oil comprising a petroleum oil, mahogany sulfonates, an alkali metal soap, and an alkylolamine. It has been found that the combination of an alkylolamine, such as triethanolamine, and a substantially neutral alkali metal soap, such as sodium resinate or rosin soap, has a unique rust inhibiting value and that the addition of an alkali metal hydroxide to compositions containing this combination further improves the rust inhibiting characteristics.

In addition to triethanolamine, other alkylolamines, such as monoand di-ethanolamines and the propanolamines, have been found to produce excellent results in combination with the other ingredients which make up the soluble oil of this invention. These alkylolamines increase the stability of the emulsion formed from the soluble oil, as well as inhibit the corrosion and rusting of metals. In the soluble oil the alkylolamines promote uniformity in the composition and prevent the separation of soap at low temperatures.

As the substantially neutral alkali metal soap, a rosin soap is preferred since this type of soap has very good grinding qualities and also is quite inexpensive. However, other water-soluble, substantially neutral soaps, such as naphthenate soaps and the soaps of the fatty acids, such as palmitic, stearic, and oleic acids, may be used. The presence of substantial amounts of the soap are essential for emulsion stability. As noted above, an important characteristic of the soap is that it cooperates with alkylolamines in the effective inhibiting of corrosion and rust formation. While considerable latitude is allowable in the selection of the soap, the soaps of the alkylolamines are to be avoided in view of their pronounced tendency toward the formation of foams. The alkylolamine soaps also do not permit ready settling of solid particles in the emulsion, such solid particles being the result of grindmetal sulfonates, such ing processes, etc. Therefore, there should be no acid in the composition available for the formation of soaps with the alkylolamines.

The mahogany sulfonates in the composition are the primary emulsifying agents, but emulsification is also promoted by the alkali metal soaps and the alkylolamines. Mahogany sulfonates, as is well known in the art, are the oil-soluble sulfonates formed in the sulfonation of petroleum oils. They are ordinarily prepared as alkali as sodium sulfonates, and they may be purified by several known methods. It is contemplated to use either the pure mahogany sulfonates or any of the commercial grades of varying degrees of purity. A commercial product containing about mahogany sulfonates has been found to be effective.

The petroleum oil in the soluble oil may be those commonly used in soluble oils, such as, for example, a petroleum lubricating oil having a viscosity of about '70 seconds at F. Saybolt Universal.

In preparing the soluble oil of this invention, a small amount of water is preferably used to make the soluble oil fluid and to prevent oil separation, or Stratification of the emulsion, upon mixing the soluble oil with larger amounts of water.

The proportions of the various ingredients in the soluble oil are quite flexible and may be varied over a, fairly Wide range, according to the particular properties desired in the finished product. However, to obtain the best results the proportions should be maintained within the following ranges:

Per cent by weight:

Mahogany sulfonates 5 to 15 Neutral alkali metal soap 2- to 6 Alkylolamine l. 0.5 to 4 Water 1 to 5 Petroleum oil Balance In the preparation of the soluble oil, rosin is dissolved in a portion'of the petroleum oil at a temperature of about 200 F. The mahogany soaps, which are readily soluble in this mixture,

are then added. To eiTect the saponification of the rosin, an aqueous solution of caustic soda is stirred into the mixture while maintaining the temperature at about 160 to 170 F. The proportion of alkali is carefully adjusted so that complete saponification occurs. Otherwise, a portion of the rosin would be available for the formation of soap with the alklolamine added at a later stage in the process. The presence of even small proportions of soaps of alklolamines is to be avoided in view of the fact that these soaps promote foaming and do not permit settling of solid particles in the emulsions formed from the soluble oils. After complete saponification of the rosin, the remainder of the petroleum oil and the required amount of alkylolamines are added. If necessary, the water content is then adjusted to obtain maximum stability, and the mixture is withdrawn as a finished product. The above procedure is given merely as an example of a suitable method of preparation, but obviously other methods will be apparent to those skilled in the art.

A soluble oil which is particularly efiective in grinding processes has the following composition:

Per cent by weight: Commercial mahogany sulfonates (containing about 65% mahogany sulfonates) 15.0 Sodium resinate 2.65 Triethanolamine 1.0 Water 2.0 Petroleum oil (lubricating oil; viscosity '70 seconds at 100 F., Saybolt Universal) Balance While this composition in the ordinary dilutions, for example, one part of the soluble oil diluted with ten parts of water, forms almost no rust, it can be further improved by the addition of small proportions of an alkali metal hydroxide. For example, the proportion of about 0.1% sodium hydroxide results in a composition which has no material effect on metals upon contact over extended periods of time. Therefore, it is preferred to add from 0.01 to 0.2% of an alkali metal hydroxide to any of the soluble oils prepared according to the invention wherever minimum corrosion and rusting of metals is desired. It is to be understood, how- 'ever, that the mere presence of an excess of an alkali metal hydroxide in any emulsion does not necessarily result in the prevention of rust formation. An emulsion containing no free alkylolamine is not improved with respect to rust prevention by the presence of excess caustic. Therefore, the improvement obtained when an excess of an alkali metal hydroxide is added in v the preparation of the composition of this in- When the use of very hard water is necessary, it is therefore desirable to increase the proportion of sodium resinate. For example, increasing the proportion of sodium resinate from 2.65% to 5.3% results in a completely stable emulsio where water of high hardness is used.

Wheneverit is necessary to increase the proportion of alkali metal soap in the soluble oil, the tendency for the separation of soap at low temperatures increases. Therefore, for the higher proportions of soap, say 4 to 6%, it is desirable to add small proportions of stabilizers such as, for example, the butyl ether of diethylene glycol (butyl carbitol). The addition of about 0.1 to 0.2% butyl carbitol to soluble oils containing 5.3% sodium resinate effectively prevents soap separation at low temperatures,

Obviously, many modifications and variations of the invention may be made without departing from the spirit and scope thereof, and therefore i only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A soluble oil comprising a petroleum oil, mahogany sulfonates, a water-soluble soap, an alkylolamine in amounts suflicient to impart antirusting properties, and an alkali metal hydroxide.

2. A soluble oil comprising a petroleum oil, mahogany sulfonates, a water-soluble soap, an alkylolamine in amounts suflicient to impart antirusting properties, an'alkali metal hydroxide, and water.

3. A soluble 011 comprising a petroleum oil, mahogany sulfonates, a rosin soap, triethanolamine in amounts suflicient to impart anti-rustin properties, and an alkali metal hydroxide.

4. A soluble oil comprising a petroleum oil, mahogany sulfonates, a rosin soap, triethanolamine in amounts sufficient to impart anti-rusting properties, an alkali metal hydroxide, and water.

5. A soluble 011 comprising a petroleum oil, a water-soluble soap, triethanolamine in amounts suilicient to impart anti-rusting properties, and an alkali metal hydroxide.

6. A soluble oil comprising a petroleum oil, 5 to 15% mahogany sulfonates, 2 to 6% watersoluble alkali metal soap, and 0.5 to 4% alkylolamine, the petroleum oil constituting substantially all of the remainder.

7. A soluble oil comprising a petroleum oil, 5 to 15% mahogany sulfonates, 2 to 6% neutral alkali metal rosin soap, and 0.5 to 4% triethanolamine, the petroleum oil constituting substantially all of the remainder.

8. A soluble oil comprising a petroleum oil, 5 to 15% mahogany sulfonates, 2 to 6% rosin soap, 0.5 to 4% triethanolamine, and 0.01 to 0.2% alkali metal hydroxide, the petroleum oil constituting substantially all of the remainder.

9. A soluble oil comprising a petroleum oil, 5 to 15% mahogany sulfonates, 2 to 6% rosin soap, 0.5 to 4% triethanolamine, 0.01 to 0.2% alkali metal hydroxide, and 1 to 5% water, the petroleum oil constituting substantially all of the remainder.

10. A soluble oil comprising a petroleum oil, about 15% commercial mahogany sulfonates, about 2.65% rosin soap, about 1% triethanolamine, about 2% water, and about'0.1% sodium hydroxide, the petroleum oil constituting substantially all of the remainder.

11. A soluble oil comprising a petroleum oil,

about 15% commercial mahogany sulfonates,

droxide, the petroleum oil constituting substantially all of the remainder.

12. A soluble oil according to claim 11 con taining from 0.1 to 0.2% butyl ether of diethylene glycol.

13. A soluble oil comprising petroleum oil, 5 to 15% mahogany sulfonate, 2 to 6% neutral alkali metal rosin soap; 0.5 to 4% alkylolamine, and 1 to 5% water, the petroleum oil constituting substantially all of the remainder.

14. A soluble oil comprising petroleumoil, 5 to 15% mahogany sulfonate, 2 to 6% alkali metal rosin soap, said soap being completely saponifled, 0.5 to 4% alkylolamine, and 1 to 5% water, the petroleum oil constituting substantially all of the remainder.

15. A soluble oil'comprising petroleum oil, mahogany sulfonate, water soluble soap, 0.5 to 4% alkylolamine, 0.01 to 0.2% alkali metal hydroxide, and water, the petroleum oil constituting substantially all of the remainder.

16.-A soluble oil as claimed in claim 15 in which the water soluble soap is a rosin soap.

17. A soluble oil comprising petroleum oil, mahogany sulfonate, 4 to 6% rosin soap, alkylolamine in amounts sufficient to impart anti-rusting properties, and a small amount of butyl ether of diethylene glycol, the petroleum oil constituting substantially all of the remainder.

THEODORE W. LANGER. 

